1. Field of the Invention
This invention relates to a method of displacing, consolidating and stablizing soft sedimentary deposits including industrial wastes in a fluidized state in watercourses or harbors for the purpose of improving the watercourse or completely reclaiming the area by stablizing the sedimentary deposit and filling the area. The area may then be used for most any purpose to which dryland may be used, for example, as parks, golf courses or other type greenzones or for erecting buildings or other structures.
2. Description of the Prior Art
One method of improving waterways or reclaiming land from waterways or harbors and bays filled with soft sediment in a fluidized state either by natural causes or by industrial wastes is to simply deposit sand or other stable material on top of the soft sediment. It is generally difficult to attain stable reclaimed land by such a method which is suitable for building structures. The weight of the sand and buildings will cause settling as the water is displaced from the soft sedimentary deposit. Since such deposits are seldom homogeous or uniform in composition, nor is the thickness of the sediment layer uniform, the reclaimed land will seldom settle in a uniform manner.
The most stable land reclaimed from watercourses and bays can be attained by dredging out the soft sedimentary material and replacing it completely with sand, stable soil concrete or other solid material. This method, however, requires that the soft material be dumped in some other place which may result in the environmental degradation of the dump site.
A special plant could be constructed at great expense and labor to de-water the slimy soft sedimentary material and treat it so that it was no longer harmful or odiferous. The material would generally have to be transported to the site of the plant at great cost. The bad orders caused by the slimy material would cause "secondary polution" along the transportation route and at the site of the plant.
Another conventional practice used to reclaim land is to compress the high water content sedimentation in situ. For example, sand drains are placed in the area and the sediment is compressed by overlaying the area with sand or soil while draining out the water. Another method is referred to as the fagot-sheet process. In this process, the treatment area is surrounded by walls, the overlaying water is drained off, and the soft slimy deposit of soft sediment material is covered by sheeting material such as canvas. Sand or soil is then deposited on the canvas for compressing the slimy deposit to force the water out of the fluidized slimy deposit.
It is technically very difficult, however, to compress the soft sediment having a very high water content by means of the sand-drain or fagot-sheet process. In order to provide proper consolidation of the soft sediment, it is actually necessary to process the slime by a primary water treatment process. Such processing is practially uneconomical in most instances.